1. Field of the Invention
The invention relates to a method of preparing steroid compounds, in particular compounds requiring a particle size within a specific range.
2. Information Disclosure Statement
In British Application No. 82-31278 filed Nov. 2, 1982, which was refiled as Application No. 83-29173 on November 1, 1983, and corresponding U.S. application Ser. No. 545,810 filed Oct. 26, 1983 (George Margetts, inventor) there are described and claimed, in particular for use in preparing pharmaceutical compositions having improved absorption characteristics, certain 2.alpha.-cyano-4.alpha.,5.alpha.-epoxy-3-oxosteroid compounds, the compounds being in particulate form and consisting of particles having a mean equivalent sphere volume diameter less than about 20 .mu.m, at least 95% of the particles having a particle size of less than about 50 .mu.m.
The earlier applications are particularly concerned with the steroid compound having the common name "trilostane", although the earlier invention also embraces the steroid compound known by the common name "epostane", which is a compound having the formula: ##STR1##
The earlier applications describe the preparation of, for example, trilostane in particulate form within the specified particle size range by the use of milling, preferably using a fluid energy (air) mill under suitable conditions e.g. of air pressure and feed rate. In the case of epostane, however, we have observed that the raw compound is not easily reduced to a suitable particle size using a milling technique,.and in some instances milling can lead to a polymorphic change which is undesirable, or to the formation of other impurities.